Work tables



\ June 7, 1955 A. K. BAKER 2,709,954

WORK TABLES Filed July 24, 1952 IN V EN TOR.

WORK TABLES Arthur K. Baker, Parsonsiield, Maine Application July 24,1952, Serial No. 300,790

Claims. (Cl. 98-36) This invention relates to work tables and moreparticularly to a contamination free work table especially adapted forthe handling of delicate or sterile materials.

Many types of materials cannot be handled by conventional methodswithout contaminating or damaging them, and, as a result, elaboratetechniques have been devised in order to minimize such damage. Forexample, special tools are commonly used in order to avoid the necessityof touching the material to be handled and such tools themselves arecleaned and otherwise maintained in a manner to prevent theircontaminating the material,

Another and more serious source of contamination arises from atmosphericair. However, since materials frequently must be exposed to theatmosphere in order to pack them or assemble them with other elements ithas been thought that a certain amount of contamination by atmosphericair was to some extent unavoidable, since the complicated apparatusnecessary to handle materials within conventional enclosed sterilizedcompartments made their use impractical in most instances. For example,in the use of so-'called micro ball bearings, in which the completedbearing is frequently of the order of but 1A; of an inch, it isessential to keep small particles of dust out of the bearing elements toavoid damaging them. Since it is necessary, as a practical matter, toexpose the bearing to the air in order to assemble it with other machineelements there is danger that dust particles may be carried into thebearing and so damage it that it must be replaced. Although thissituation has been accepted for a number of years, the necessity ofconvenient handling of the bearings outweighed the loss from damagedbearings and such loss was considered a necessary evil.

Similarly, in the packing of pharmaceuticals in ampules it has beenfound essential to carry out the operation in enclosed compartments byautomatic machinery if the essential sterility is to be maintained.However, such an operation adds greatly to the expense of packing suchampules particularly when relatively small quantities are to be handled.

Accordingly, it is an object of the present invention to provide acontamination free work table in which the materials are readily handledwhile maintaining them under contamination free conditions.

It is a particular feature of my invention that the work table soprovided is simple and effective and requires no complicated mechanismfor handling the materials.

For the purpose of more fully explaining a preferred embodiment of myinvention, reference is made to the following drawings in which:

Fig. 1 is an isometric View of the contamination free work table of myinvention;

Fig. 2 is a vertical cross sectional view taken on the line 2 2 of Fig.l;

Fig. 3 is a vertical cross sectional view taken on the line 3-3 of Fig.1.

The work table of my invention includes one or more rates Patent workcompartments 10 and 11, and a ventilation compartment 12 therebetween,such compartments being separate units as hereinafter more fullyexplained. The work compartments are supported at one end on suitablelegs 14 and at the other end by ventilation compartment 12. The workcompartments have a generally vertical rear wall 16 and a front wallhaving a sloping upper portion l and a generally vertical lower portion20 as well as suitable ends 17', one of which may be formed by the sideof the ventilation compartment 12. Preferably, the front wall upperportion 18 has a transparent panel 19 therein and ends 17 are providedwith lights 52 arranged to provide additional illumination to bottomsurface 24.

The lower portion 2@ of said front wall has an access opening 22extending substantially along the entire length of the Work compartmentwhich is thus completely enclosed except for said access opening.Beneath the bottom 24 of the work compartment is provided a sliding doorstructure having a door portion 21 hinged by a suitable hinge 23 to asliding door support member 25. Thus, when the work table is not in use,access opening 22 may be closed by sliding said door structure forwardand covering said access opening with door portion 21, a suitablefriction catch 2'7 being provided to releasably maintain said door 21 inclosed position.

ln order to maintain the Work compartment and its work surface 24 inuncontaminated condition, I supply a liow of air outwardly entirelythroughout access opening 22, such air having been suitablydecontaminated in accordance with the particular service to which thework table is to be put. Such decontamination includes air treatmentmeans for filtering the air, precipitating line dust therefrom, andadditional means, it' necessary, for sterilizing it as hereinafterexplained.

In order to provide a suitable uniform continuous ow of air outwardlyentirely throughout access opening 22, I provide a duct 26 disposedpreferably along the upper surface of the work compartment 1t), saidduct having, in its lower surface, openings 28 communicating with theinterior of said compartment. A baffle 30 comprising a shelf mounted ingenerally horizontal position on the rear wall i6 of said workcompartment is arranged to cooperate with the sloping front wall portion18 to direct air smoothly outwardly throughout the entire extent ofaccess opening 22.

The air treatment means for filtering air and supplying such filteredair to the work compartments is provided in ventilation compartment 12,such compartment having a plurality of openings 32 around the bottomportion thereof. A blower 34 is mounted therein to force air from saidopenings 32 through port 33 to plenum chamber 38 communicating withVentilator' compartment duct 29 extending along the top of saidcompartment, said air passing through filter elements between saidopening 32 and said blower. Said filter elements comprise a mechanicalfilter element 35 consisting of a layer of fiber glass which is eectiveto remove relatively large dust particles from the air passing throughit, and an electrical dust precipitator for removing small dustparticles.

The electrical dust precipitator includes a series of oppositely chargedplates adapted to remove tine dust particles electrostatically. Suchprecipitator operates by a high Voltage on ionizer wires 41 mounted onsupports 40 to charge the dust particles and a second high voltage to aiirst group dust collector plates 42, the second group of dust collectorplates 44 being grounded as is one side of the high voltage power unit46 which supplies said voltages. A diffusing element comprising a flatplate 36 with perforations 37 therein arranged to insure that air goesevenly through the dust precipitator is preferably provided betweenfiber glass filter 35 and the precipitator.

3 Such electrical dust precipitators are well known and need not hereinbe further described.

The filtered and dust-free air thus passes from iiltering compartment 12to the plenum chamber 3S, and then into duct 29 overlying saidcompartment. From the ventilation compartment duct 29 it passes intowork compartment ducts 26 adjoining said duct 29 and finally throughopenings 28 into the work compartments 10 and 11, at a pressure greaterthan atmospheric pressure, so as to flow outwardly through accessopenings 22 therein.

In order to provide sterilized as well as dust free air to said workcompartments, suitable irradiation means such as ultra-violet lights 48may be provided, for example, in duct 26, such means being effective tokill air borne bacteria before it reaches work compartments 10 and 11 toprovide a sterile as well as a dust free work table. The variousdecontaminating means and the illuminating means 52 may be connectedwith a switch 49, such switch preferably being mounted above accessopening 22 in position to be actuated by door 2l so that said means willbe started as soon as said door is opened to prevent contamination ofthe work compartment.

In order to provide ilexible unit construction, I prefer to constructthe work compartments separate from the Ventilating compartment. Forexample, in Fig. l, two work compartments are provided with a singleVentilating compartment. The work compartment duct 26 is terminated atthe end of said Work compartment adjacent Ventilating compartment duct29, a plate 50, gasketing material and suitable sheet metal screws S1being provided for attaching said work compartment duct 26 toVentilating compartment duct 29. A similar arrangement is provided toconnect the opposite work compartment 11 to said Ventilatingcompartment. Thus either one or more workl compartments may be used witha single Ventilating compartment and the attaching plates 50 may bequickly and easily removed to release one from the other. If desired forconvenience in installation, one or more work compartments may bearranged on either side of the Ventilating compartment. For example, asingle ventilating compartment can supply four work spaces on the leftor four on the right or one and three or two and two. A suitable plate,not shown, may be placed in the unused end of Ventilating compartmentduct 29.

To use my novel work table, an operator seated in front of said worktable reaches through access opening 22 in order to handle the materialstherein by suitable tools. While the necessary handling is beingperformed theoperators hands and arms together with the materials to behandled will continually be bathed in decontaminated air, which air isthen moved outwardly through access opening 22 forming an air shield toprevent contamination by matter either picked up from the operator orfrom the normal atmospheric air outside of the work compartment.

Thus it will be seen that I have provided a novel contamination freework table which at the same time permits convenient and direct handlingof materials therein. Various changes within the spirit of my inventionand the scope of the appended claims will be apparent to those skilledin the art.

I claim:

l. A dust free work table comprising an enclosed work compartment havinga bottom providing a work surface and an access opening in saidcompartment adjacent said work surface for access thereto, means forremoving dust from atmospheric air, duct means communicating with saiddust removing means and said table for receiving dust free air from saiddust removing means and supplying the dust free air to said table, andmeans for flowing air through said dust removing means and providing aow of dust free air through said duct means and into said enclosed workcompartment at a pressure greater than atmospheric pressure, and meansfor directing the dust free air outwardly entirely throughout saidaccess opening to form an air shield entirely across said access openingto prevent movement of atmospheric air inwardly through said accessopening to said work surface.

2. A dust free work table as claimed in claim l, further including doormeans operable to close said access opening and switch means actuated bysaid door means arranged and connected to operate said dust removingmeans when said door means is in open position.

3. A dust free work table as claimed in claim l in which said airtreatment means includes irradiation means constructed and arranged tosterilize air in said compartment.

4. A dust free work table as claimed in claim l in which Said dustremoving means includes an electrical dust precipitating means.

5. A dust free work table as claimed in claim l, further characterizedin that said work compartment has a front wall with a sloping upperportion and wherein said access opening is positioned between the lowerportion of said sloping front wall and said bottom.

References Cited inthe rile of this patent UNlTED STATES PATENTS2,209,054 Doud et al. July 23, 1940 2,234,037 Anderson Mar. 4, l94l2,334,776 King et al. Nov. 23, 1943 2,350,735 Egge June 6, 19442,380,147 Burke July l0, 1945 2,397,197 Newman Mar. 26, 1946 2,397,731Fowler Apr. 2, i946 2,436,508 Fairbanks Feb. 24, 1948 FOREIGN PATENTS206,257 Switzerland Nov. l, i939

